KVM: MIPS/TLB: Add VZ TLB management

Add functions for MIPS VZ TLB management to tlb.c.

kvm_vz_host_tlb_inv() will be used for invalidating root TLB entries
after GPA page tables have been modified due to a KVM page fault. It
arranges for a root GPA mapping to be flushed from the TLB, using the
gpa_mm ASID or the current GuestID to do the probe.

kvm_vz_local_flush_roottlb_all_guests() and
kvm_vz_local_flush_guesttlb_all() flush all TLB entries in the
corresponding TLB for guest mappings (GPA->RPA for root TLB with
GuestID, and all entries for guest TLB). They will be used when starting
a new GuestID cycle, when VZ hardware is enabled/disabled, and also when
switching to a guest when the guest TLB contents may be stale or belong
to a different VM.

kvm_vz_guest_tlb_lookup() converts a guest virtual address to a guest
physical address using the guest TLB. This will be used to decode guest
virtual addresses which are sometimes provided by VZ hardware in
CP0_BadVAddr for certain exceptions when the guest physical address is
unavailable.

kvm_vz_save_guesttlb() and kvm_vz_load_guesttlb() will be used to
preserve wired guest VTLB entries while a guest isn't running.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/include/asm/cpu-info.h

@@ -33,6 +33,7 @@ struct guest_info {
 	unsigned long		ases_dyn;
 	unsigned long long	options;
 	unsigned long long	options_dyn;
+	int			tlbsize;
 	u8			conf;
 	u8			kscratch_mask;
 };

arch/mips/include/asm/kvm_host.h

@@ -812,6 +812,18 @@ extern int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi,
 extern int kvm_mips_guest_tlb_lookup(struct kvm_vcpu *vcpu,
 				     unsigned long entryhi);
 
+#ifdef CONFIG_KVM_MIPS_VZ
+int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi);
+int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
+			    unsigned long *gpa);
+void kvm_vz_local_flush_roottlb_all_guests(void);
+void kvm_vz_local_flush_guesttlb_all(void);
+void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
+			  unsigned int count);
+void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
+			  unsigned int count);
+#endif
+
 void kvm_mips_suspend_mm(int cpu);
 void kvm_mips_resume_mm(int cpu);